On Monday, McDonald's workers who suffered severe burns on the job announced they have filed 28 health and safety complaints against the fast-food company. With complaints spanning 19 cities, workers allege that understaffing and pressure to work too fast created hazardous conditions that resulted in injuries.

One of the most disturbing of these allegations is leveled by Brittney Berry, a former employee from Chicago, who says that when rushing to meet her managers' demands, she severely burned her arm on a hot grill.

"The managers told me to put mustard on it, but I ended up having to get rushed to the hospital in an ambulance," Berry said in a statement. "This is exactly why workers at McDonald’s need union rights, so we have a voice to make the company take responsibility for the dangers it creates in its stores."

"McDonald’s and its independent franchisees are committed to providing safe working conditions for employees in the 14,000 McDonald’s Brand U.S. restaurants," McDonald's spokesperson Heidi Barker Sa Shekhem said in a statement. "We will review these allegations. It is important to note that these complaints are part of a larger strategy orchestrated by activists targeting our brand and designed to generate media coverage."

The complaints are closely linked to recent activism against fast-food chains. Like many recent complaints against McDonald's, they were filed with the assistance of 'Fight for $15,' a campaign launched by the Service Employees International Union in late 2012. McDonald's has argued that these campaigns and other efforts by the SEIU, including the move toward considering franchisors "joint employers" in labor disputes, are veiled attempts at increasing union membership.

However, the SEIU argues McDonald's purposeful overlooks safety problems, meaning the franchisor should be held accountable for health and safety violations. Fight for $15 points to statistics as evidence of a system and industry-wide problem: 79 percent of fast-food workers report they have been burned in the last year, and a third say they have been told to treat burns with condiments like mustard or mayonnaise instead of using burn cream.